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But everyone changes their mind after a joyride, claims Suhartono Setiawan, engineering manager at Singapore company Wigetworks. “It’s not as scary as it first looked and it’s very comfortable… only during take-off it can be bumpy. So they are surprised at the experience – they think it’s going to be bumpy and unstable but it’s not. After 15 minutes, they want to keep on going.”
The Airfish is a wing-in-ground (WIG) vehicle. Like the albatross or Second World War bombers running low on fuel, the craft takes advantage of the ground effect for fast, efficient cruising just above the surface of the water. Flying at 7m or lower it enjoys higher air pressure on a ‘cushion of air’ beneath its body and less lift-induced drag, reaching a maximum speed of 196km/h or cruising speed of 148km/h – much faster than a 50km/h ferry, for example.
“We know there is a problem with people who want to travel faster in the maritime environment,” says Setiawan, who also stresses the safety and convenience of low-altitude flight: “Our runway is available always, any time, anywhere, 2m beneath us.”
The prototype, following on from a succession of German WIG craft between the 1960s and the millennium, carries up to eight passengers and two crew members. It is 17.2m long and its reverse-delta wingspan is 15m. Using a V8 car engine and two fixed propellers, it takes off from the water over a distance of 500m and has a reported range of 556km.
Will this “technology of the future,” as Setiawan puts it, fill a niche in the marine transport sector – or will people stick to ferries and seaplanes?
Power up
Setiawan is quick to explain current issues. The Airfish 8 has poor manoeuvrability below 10km/h, for example, a serious problem for docking or avoiding primitive, water-going boats. Its 160m turning radius is hardly sixpence-sized, and Wigetworks wants bigger payloads and quicker take-off in higher waves – particularly useful for military or government bodies, which might use an Airfish in open-sea areas.
That means adding more power, so the company is improving the design with a second engine and variable-pitch propellers for improved manoeuvrability and efficiency. The firm hopes to test an improved prototype by the third quarter of this year.
Those improvements might not overcome the biggest problem, however. Passengers might enjoy unrivalled smooth marine travel during flight but rapid acceleration and deceleration on water will be bumpy. The craft might also have to take off facing the waves during high winds, and it’s unclear how it will fare in rougher seas.
Bigger Airfish to fry
With predicted commercial and official use, however, Wigetworks is confident in the technology, and Setiawan predicts that other companies will be inspired to mimic it. “But,” he says, “it is not as easy as you might think.” Building a plane-boat chimera requires a complex mix of knowledge, something the company still “struggles” with despite a good understanding of the technology.
The firm is nonetheless planning even more ambitious vehicles to stay ahead of the pack. A “much bigger Airfish will change the game entirely,” claims Setiawan.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.